β
With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundaryβthe utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.
β
β
Edwin Powell Hubble (The Realm of the Nebulae (The Silliman Memorial Lectures Series))